Atoms, Bonds & Water — Drills · Grade 10 Science
Chapter: Investigating the Chemistry of LifeWhat these drills covers
By the end of Atoms, Bonds & Water you should be able to:
- I can explain how atoms combine into compounds through covalent and ionic bonds.
- I can describe how water's polarity gives it cohesion, adhesion, and its power as a solvent.
- I can use the pH scale to classify solutions as acidic, basic, or neutral.
6 questions, multiple choice, numeric and written answer, each with a worked explanation.
Vocabulary used: atom, element, covalent bond, ionic bond, hydrogen bond, polar molecule, pH.
Problem 1
- An ionic bond
- A polar covalent bond
- A hydrogen bond
- A peptide bond
Answer and explanation
A polar covalent bond
Within one molecule, oxygen and hydrogen share electrons unequally: a polar covalent bond. Hydrogen bonds act between separate water molecules.
Problem 2
Answer and explanation
4
Two through its hydrogen atoms and two through the oxygen's lone pairs, giving four.
Problem 3
Answer and explanation
4180 J
Q = mcΔT = 100.0 × 4.18 × 10.0 = 4,180 J.
Problem 4
- 2 times more hydrogen ions
- 20 times more hydrogen ions
- 100 times more hydrogen ions
- half as many hydrogen ions
Answer and explanation
100 times more hydrogen ions
Each pH unit is a tenfold change in hydrogen-ion concentration, so two units is 10 × 10 = 100 times more.
Problem 5
Answer and explanation
8
pH is the negative exponent when the concentration is written as 1 × 10⁻ⁿ, so pH = 8, slightly basic.
Problem 6
Answer and explanation
In ice, hydrogen bonds hold molecules in an open lattice that is less dense than liquid water, so ice floats. A floating ice layer insulates the water beneath it, which stays liquid, so fish and other aquatic organisms survive the winter below the surface.
Response criteria
- State a biologically accurate conclusion.
- Show the data, mechanism, or calculation that supports it.
- Include units, conditions, or limits where relevant.